Out-of-hospital cardiac arrest treated by emergency medical services has an estimated incidence of 54.99 per 100,000 person years, which translates to some 155,000 episodes annually in the United States. Bradyasystole is the first recorded rhythm in up to 52 percent of cardiac arrests, and many additional patients with an initial cardiac arrest rhythm of ventricular fibrillation deteriorate to bradyasystole after defibrillation efforts. Survival to hospital discharge occurs in less than 3 percent of patients presenting with bradyasystole; however, due to its frequency, this rhythm accounts for over 17 percent of all cardiac arrest survivors. As a result, even a small improvement in survival from bradyasystolic cardiac arrest would result in thousands of lives saved annually.